I think a large, open world to explore, that is full of optional quests, bosses and dungeons makes any decent RPG. For a Final Fantasy, it needs those and chocobos, airships, and ultimate weapons that you have to solve hidden puzzles or defeat bosses for (not this crafting random materials together and battle grinding for items to level them up crap).

Take Final Fantasy VII for example: there was so much to do once you got either a gold chocobo (through breeding, yes - that was optional too!) or the airship! You could play games at the Gold Saucer, take on Ruby and Emerald Weapon, find everyone's Ultimate Weapons, find hidden materia in hidden caves, recruit optional party members and do their optional quests. In Final Fantasy VIII, you had a card game you could play, and same with Final Fantasy IX.

In a way, I prefer to not see the monsters coming, and I like the console to pick and choose my battles. But I also liked the charm of seeing them in the world of Final Fantasy XII and XIII. It makes the game feel less empty. As long as battle systems don't suck, I don't really mind how they start. I also prefer it if I can see the level my character is.